Recovery of oil from the earth by mining operations



L. RANNEY 1,812,305

RECOVERY OF OIL FROM THE EARTH BY MINING OPERATIONS `lune 30, 1931.

3 sheets-sheet 1 @Qu bUbQO MDN WHW/FN m A/V//Qn L. RANNEY June` 30,19.31.

RECOVERY OF OIL FROM THE EARTH BY MINING OPERATIONS 3 Sheets-Sheet 2EXF1/L S/ON Filed Aug. 5' 1925 E o RANNEY 5140014150@ i.. RANNEY June3o, 1931.A

`RECOVERY OF OIL FROM THE EARTH B Y MINING OPERATIONS 3 Sheets-Sheet 5Filed Aug. 5' 1925 QSSSQN NOON RSU NNOJ LGR/miv anne/nto@ NNUONN RY MOONRSU NHO- l l r l l l l @n WKO Patented June 30, 19.31

`UNrraD y STATES LEO RAN'NEY, OF GBEENWICH, CONNECTICUT, ASSIGNOB TOSTANDARD COMPANY, A CORPORATION OF' DELAWARE PATENT OFFICE DEVELOPHEN TRECOVERY OF OIL FROM THE EARTH BY IINING OPERATIONS Application medAugust 5, 1926. Serial No. 127,233.

This invention relates to the recovery of oil from the earth by miningoperations including the formation 'fof' a vwork-ing area, adjacent tobut spaced from an oil-bearing stratum or oil sand, from which areaexpulsive Y nection with the accompanying drawings,

in which Fig. 1 is a fragmentary dlagrammatic v ertical section throughan instal ation in which a shaft and mine gallery or tunnel are pro- 17vided; U

Fig. 2 is a plan view of an oil recovery s stem, the plane of the viewbeing taken online II-II, Fig. 1;

Fig. 3 is a partial vertical sectlon through an alternative form ofinstallation comprlsinv chambers formed in the oil sand;

2Fig. 4 is a complete plan view correspondin to Fig. 3; and

Fig. 5 is a vertical section showing the c'method of tapping gas sandsto secure a suppl of expulsion agent. l

Iteferring to Figs. 1 and 2, reference numeral 1 denotes a mine shaftpassing throu h an upper ca -rock 2 and an oil sand 3. T c shaft is seaed from the oil sand by a concrete wall 4, or other suitable means. Amine gallery or tunnel 5 is driven from the bottom of the shaft 1through the lower cap-rock 6, or other impervious stratum underlying theoil sand. 'Ihe allery is preferably extended along each e ge of thetrack to be worked, for instance a forty-acre unit, in the generalmanner shown in Fig. 2. A suitable number of more or less centrallylocated wells, for instance the iive wells designated 7 8, 9, 10, and11, are drilled from the earth surface to tap the oil sand.

A pi e 12 is laid horizontally throughout the alltery 5 and has branchnipples 13 sealed 5 in t e lower cap-rock 6 by sealing material 14. Eachof the nipples has a valve 15 of the gate type. Holes or mine wells aredrilled through the nipples into the oil sand, the drill being insertedthrough the outer end of the cross fitting 16 provided at the base ofeach nipple. In my Patent N o. 1,634,236 granted June 28, 1927, ofwhichthe present application is a continuation in part, I have described indetail the formation and operation of mine wells of the type referredto.

' A suction pump 17 is connected to the pipe 12 and forwards the iiuidentering that pipe through a connecting pipe 18 to the surface storagetank 19. A pipe 20, connected to aA source of the expulsion agent (gas,air, water, etc.), is connected to the pipe 18. valved by-pass 21 isprovided for carrying the expulsion agent around the suction pump In theoperation of the installation described I prefer to proceed as follows:First strong suction is applied to the pipe 12 and the nipples connectedto it. In this way there is soon formed an unexcavated drainage tunnel(area from which oil has been largely exhausted) extending entirelyaround the tract being worked. Since the mine wells tap the bottom ofthe sand at numerous closely spaced points, the evacuation of oil israpid and quite complete for a considerable distance from the. gallery.The oil collected is forwarded to the storage tank 19. The iow of oilfrom the mine wells may be controlled, and heat may be applied, asdescribed in Serial No.,14,448 above referred to, but in most fieldsthis expedient will not be necessary for the purposes of the presentinvention.

When the unexcavated drainage tunnel has been established around thetract to be worked, an expulsion agent, for example air or a special gaswhich breaks the surface tension of oil adhering to the sand grains isforced through pipes 20, 18 and 12 and nipples 13 into the oil sand 3. Awall of air is thus formed around the tract, enclosing the oil andforcing it along lines converging towards the center. The nipples shouldbe placed suiiiciently close together to ensure that the air or gasinjected from each overlaps with that injected through the adjacenttween the tract being worked and those ad-v jacent it. Differences inporosity of the sand at various points of the tract may require thatvalves in different mine wells be partially closed to` admit less air.means by which to control the direction of the wave of air or gas in thesand, so that it may reach all points.

During the forcing in of the air some oil is likely- 'to drain into themine wells. This oil may) be collected in one or more tanks 20 and susequently forwarded to the main collecting tank 19. v Separate pipesystems for withdrawing oil and introduclng the expulsion agent may beprovided, but this is gen- 'erally unnecssary.

The four outer wells, 7, 8, 9 and 10, first receive the oil as it isforced inwardly from the boundaries of the tract. When air begins to bedischarged from these wells they are closed and the central well 11 isused for the withdrawal of oil. However, variations in the porosity ofthe sand might alter the arrangement of producing wells.

By applying-the expulsion agent in the manner described I' secure a verycomplete recovery of the oil. The expulsion agent operates upon a body'of oil which is continuo'usly becoming denser and which iscontinuouslyy filling any voided streaks of sand-and,

therefore, is effectively displaced by the agent. This method eliminatesany by-passing of oil, such as occurs when applying air on a lengtheningor a stationary line of attack. I operate witli a constantly shorteningline of attack upon the oil sand.

For best results the mine wells should bel drilled entirely around theproducing area, but some of the advantages of the invention may beobtained with other arrangements. For example, an expulsion agentintroduced through mine wells on two or three sides of the area willpermit a high recovery of oil from the sand.

According to Figs. 3 and 4, there is illustrated a mine allery or atunnel 21 of the -type above re erred to, connected with a chamber 22formed in the oil sand itself.v

The chamber is walled with concrete Vor the like 23 so as vto seal .itfrom the oil sand.

Holes 24 are drilled from the chamber in a generall horizontal directionalong two or more si es of the tract to be worked. I prefer to form oneof the chambers at each of .the four corners of the tract, as shown inFig. 4, the holes 24 extending from each chamber approximately half-wayalong thesides of the tract.

The holes 24 are conveniently formed by 55 inserting a drill through thenipple 25 sealed This givesv inthe wall of the chamber 22.4 The nippleis connectedwith a fitting 26, havinl a gate valve 27 and end closure28.adapte to permit assage of the drill. Additional sections of rillstem are added as the drill penetrates. the sand, and it is practical toform horizontal openings of the required lengtln After removal ofthedrill the expulsion agent is suppliedthro-ughpipes 29 and 30 to theheader 31, from which it passes into the nipples and thence into theopen holes extending through thesand. Suction ma be prelimmarily appliedto pipe 29 to with raw oil draining into the open holes 24.

Mine wells may be provided in the tunnel vif desired. VVhere it 1s moreenonomical to sink shaftsifor the construction of the severalchambers'the gallery may be omitted. In my application Serial No.100,531,` filed April 8, 1926, a general method of operating with theuse of chambers inthe sand is described and claimed. The utilization ofthis processherein is in the supplying of an expulsion agentcontinuously along the bottom of the sand and with a continuouslyshortening line of attack upon the oil sand.

Test pipes 32 (Fig. 1), each carrying a tluidvgauge 33 and a pressuregauge 34, are

preferably provided rat numerous levels in t on the first mentioned sidereading higher than those on the other sides. The pressure under whichthe expulsion agent is supplied will be modified so as to equalize thisdifference and secure a substantially uniform advance toward the centerof the tract. The amount of pressure necessary will vary greatly withconditions. A pressure of lbs. per square inch maintained adjacent thegallery will be adequate for the average oil sand. Test pipes should beplaced at least every-300 or 400 yards throughout the extent of thegalleries. The use of these pipes is described and claimed in myapplication vSerial No. 116,857 filed June 18, 1926.

While air 'has been chiefly mentioned as an expulsion agent, others maybe more suitable under certain' conditions. -Gas and water may beconvenietly used. Where one or more gas sands are adjacent the oil sand,it is convenient to secure the gas in the general manner shown in Fig.5. In this figure a gas line 35 taps the as sand 36and is connected to apipe 37 which delivers into the nip les 38. Assuming that there is alsoan un erlying gas sand 39, this may be connected with the pipe 37 by apipe 40. Valves 41V and 41 and pressure gauges 42 and 42 are provided onthe gas lines 35 and 40, respectively.

It is sometimesdesirable to ream out an opening about the inlet ends ofthe gas lines, as shown at 43 and 43', Fig. 5. A better flow of gas isobtained in this way. Flow of oil may be expedited also by reamingchambers 44 at the inlet of each mine well. g

I prefer to operate from beneath the4 oil sand in most cases, but wheredifficulty of tunneling or other causes makes this inadvisable, mymethod can be operated from a working area adjacent the upper surface ofthe oil sand. The preliminary formation of an unexcavated drainagetunnel is generally desirable, since a substantial amount of oil can berecovered as an incident to this operation. However, the expulsion agentmay be forced into the sand' without preliminary withdrawal of oil, andall the oil may be driven tothe central collecting openings or oilwells'.

It will be understood that the number of mine wells may be variedgreatly, the only requirement being that they be sufficiently closetogether to permit the formation of an effective wall of the expulsionagent introduced through them. In working a square forty-acre tract of athick, highly consolidated oil sand, I prefer to make about 132 minewells' on each side, the wells usually being equally spaced along thesides.

Various changes and alternative. arrangements may be made within thescope of the appended claims, in which itis my lntention to claim al1novelty inherent in the invention, as broadly as the prior art permits.

I claim:

1. In the recovery of oil from an oil-bearing stratum, the improvementwhich comprises forming a mine gallery along the margin of the tract tobe worked, the galler bel ing adjacent said stratum but spaced t erethecenter of'said area, and withdrawing the n oil from said well.

4. Method according to claim 3, in which the oil-expelling agent is gasobtained from a stratum adjacent the oil sand.

' 5. Method'according to claim 3, in which the oil-expelling agent issupplied under pressure regulated in accordance with conditions in thesand, as indicated by test devices inserted therein.

' LEO RANNEY.

from by material substantially impervious to fluid, tapping said stratumfrom the gallery by a large number of closely spaced openings, drillinga surface well to the stratum within the area defined by the gallery,and introducin a fluid oil-expelling agent through said c osely spacedopenings, thereby forming a fiuid barrier moving inwardly from themargin of the tract to force the oil there-v in throuirh the surfacewell.

2. Method of recovering oil from a selected areaof an oil-bearingstratum, comprisingl forming a mine gallery adjacent to but below orabove said area, said gallery extending about the margin of the area,forming a large number of closely spaced openings from the gallery intothe olcaring stratum, drilling a surface well within said area,withdrawing oil from said openings to form an unexcavabed drainagetunnel, then forcing an ex-

